Electric starter



June 14, 1932. c p BRQCKWAY 1,862,921

ELECTRIC STARTER Original Filed Sept. 20. 1920 INVENTOR.

ATTORNEY Carl 7? Brochwcp/ gine after Patented June 14, 1932 ENITEESTATES rarest orricn CARL I. BROCKWAY, F PATERSQN, NEW JERSEY, ASSIGNORT0 INDUSTRIAL RE- SEARCH COR'BORATION,

0F TOLEDO, CHIC, A GOR-PORATIGN 0. 5

DELAWARE ELECTRIC STARTER Application filed September 20, 1920, SerialNo. 411,599.

This invention relates to starting mechanism for internal combustionengines, particularly as applied to automobile use wherein a small motoris utilized to give the initial energization of the engine.

In devices of this sort it is customary to employ a small electric motorwhich is attached to the engine frame adjacent the fly-wheel of theengine so that power may be applied to the crank shaft at a.comparatively high gear reduction. 7

An important object of this invention is to employ a type of drive whichis entirely automatic in forming a connection between the motor shaftand the engine fly-wheel so that the employment of any manually operatedlevers is unnecessary.

In addition, it is an object of the invention to make this drivemechanism automatic. in its disengagement from the fiy-wheel of theenthe engine has started under its own power. This is a requisite forthe reason that a sudden impulse under high power of the enginetransmitting energy to the motor would cause disastrous results in themotor armature if disconnection is not immediately made.

Another object of the invention is to include in the drive mechanism aresilient element which will tend to absorb the shock put upon the motorshaft when the dead load of the motor is taken up thereby permitting agradual variation 1n the application of power I to the engine.

Still another object is to provide means for preventing any connectionbetween the engine and the motor shaft except when starting the en gine.

An object also, is to devise a form of connection between the motorshaft and engine which will not be subject to binding so that themovement of the difi'erent gear members into and out of mesh with eachother is ac-,

complished freely and with uniform effectiveness.

lustrated Renewed. May 15, 1929.

' wherein is disclosed, a longitudinal view of the drive mechanismpartly in section, to-

gether with a sectional detail of a portion of the fly-wheel and easingof the engine.

Referring to the drawing I have shown,

as preferably used, an electric motor 10 having an armature 11 and shaft12, the motor being secured at one end to the engine casing 13. As themotor itself forms no part of my invention, I will not attempt todescribe it in detail, the various elements thereof conforming toconventional engineering usage.

The shaft 12 extends beyond the motor to an appreciable extent, themiddle portion 1 l of which is threaded and the end portion 15 of whichis smooth but with a lesser diameter than that of the major portion ofthe shaft.

The sleeve 16, having an internal thread out along the major portion ofits length, is screw threaded upon the threaded portion of the shaft 12upon which it has, therefore, both rotary and longitudinal movement. Theouter end of the sleeve has an internally directed flange 18, the innercircumference of which forms a bearing upon the end portion of theshaft. A. washer 19 and nut 20 in the end of the shaft 12 form alimiting stop for the outward movement of the sleeve 16.

Mounted on the shaft 12 intermediate the sleeve 16 and the motor is apinion 21 the body of which is extended outwardly as at 22, to form asleeve portion. Adjacent the outer )ortion of this pinion sleeve and theinner end of the sleeve 16, grooves 23 and 24 are cut into which extendthe internally directed flanges 25 and 26 of a band 27, the latterserving as a loose connection between the two sleeve elements and makingpossible relative rotary interconnecting the two collars 28 and 30 is acoil s )ring 32 which is fixed at either end to he two collars. Thisspring is preferably of a construction in wiich each element isflattened so that its greatest dimension in cross section is radial fromthe shaft. This construction pe 'mits the transmission of a high torquein rotation and at the same time, an easy free movement in an axialdirection.

F or a purpose hereinafter to be described the band 27 has a lesserexternal diameter than the major portion of the sleeve 16 and both thesleeves l6 and 22 adjacent the band are cut so as to have similarly adiminished external diameter so that an appreciable distance existsbetween the internal diameter of the coil spring and the portions of thesleeves and the band which have the diminished external diameters.

Surrounding the smooth external portion 15 of the shaft is a second coilspring 33 which has hearing at one end, against the shoulder 34 of theshaft formed between the outer portion and the threaded portion, and atthe other end against the internal flange of the sleeve 16. This springnormally tends to urge the sleeve in an outward direction.

The motor shaft is placed in such relation to the fly-wheel 35 of theengine that movement of the pinion along the motor shaft will bring thesame into engagement with the gear teeth 36 formed on the periphery ofthe flywheel and in order to permit ready engagement of the intermeshedgear teeth, the teeth of the pinion are preferably chambered and roundedas at 37.

Between the internal thread and outer flange of the sleeve 16hereinbefore described the inner diameter of the sleeve is diminished,

thus forming a shoulder 38 which serves as a limiting stop for the screwthreaded portion 1 1 of the motor shaft.

The operation of the starting mechanism is as follows. As shown in thedrawing, it is assumed that the motor has a normal direction of rotationsuch as to cause the pinion 21 to move inwardly along the shaft towardsthe motor. The only connection between the motor shaft and the sleeve 16is that of the screw threads hereinbefore mentioned and in as much asthe sleeve together with the other elements such as the spring 32, andthe pinion 21, have considerable inertia in propor- I 3 tion to theenergy applied through the motor shaft, rotation of the motor shaft inits normal direction will cause the sleeve to screw along the motorshaft thereby carrying the pinion without rotation, or at best, withonly a slight rotation, toward the fly-wheel gear teeth and into meshtherewith. As soon as the pinion and engine member are in completeengagement and the shoulders 34 and 38 in contact the motor tends totake on the load of the fly-wheel, but rotation of the pin ion ismomentarily prevented. Inasmuch as the shaft carries the spring 32 withundiminished speed in rotation, the friction of the collar 30 on thepinion teeth and also that portion of the spring which bears on thesleeve, both tend to cause the spring to wind up upon the sleeve,thereby operating the same as a clutch. Without the portions of thesleeves hereinbefore referred to, wherein the external diameters are oflesser than the normal diameter, this clutching action would beimmediate so that a considerable jar would be efiective upon the motorshaft, but with these portions, the spring is permitted to coil down tofit, so that the spring functions as a shock absorber, permittinggradual application of the power to the engine fly-wheel. It istherefore apparent that energy from the starting motor is transmittedfrom the shaft through the sleeve 16 to the spring and thus to thesleeve 22, to the pinion and finally to the engine fly-wheel.

As soon as the engine has started under its own power it will exert arelatively higher speed of rotation upon the pinion than thattransmitted by the motor, which force will tend to cause the spring tounwind itself, thereby loosening the drive connection between the motorand pinion. As this disconnecting eflect is immediate, the possibilityof any injurious shock being transmitted to the motor armature isentirely obviated; and it is also evident that a reversal of the enginefly-wheel, or a connection between the flywheel when rotating in itsnormal direction at full speed, can have no driving connection with thepinion on the motor shaft since the pinion always moves freely unlesspower is transmitted to it from the motor shaft. When the engine startsup sin'iultaneously with the release of the spring 32, the spring 33which is under compression while the pinion is in driving position,carries the sleeve and its loosely connected pinion sleeve out- Wardly,thereby bringing the gear elements out of mesh with each other.

I am aware that the particular embodiment of my invention both describedand illustrated in the accompanying drawing, is susceptible ofconsiderable variation without departing from the spirit thereof, andtherefore, I desire to claim my invention broadly as well asspecifically, as indicated by the appended claims.

I claim as my invention:

1. In a starting mechanism for non-self starting engines, thecombination of a motor; a shaft therefor provided with an elongatedextension, said extension having a median portion screw threaded, and anouter portion of less diameter than the middle portion; an internallythreaded hollow sleeve having screw threaded engagement with the shaft;a pinion positioned on the shaft between the first named sleeve andmotor and having a portion thereof extended outwardly Ill to form asleeve; tween said sleeves permitting limited relative longitudinalmovement of the pinion; an annular member positioned on the pinionsleeve and adapted to have frictional engagement with the pinion; aspiral drive spring encompassing said sleeves, one end thereof beingfixed to the threaded sleeve and the other end to the annular memberanda compression spring encircling the outer portion of the motor shaft,one end thereof bearing against the shoulder formed at the junction ofouter and middle shaft portions and the other end bearing against aportion of the threaded sleeve.

2. A starting mechanism, comprising a motor having a shaft extendingaxially to one side thereof, said shaft having an inner smooth portion,a middle screw threaded portion, and an outer smooth portion of lesserdiameter than the middle and inner portions; a sleeve having screwthreaded engagement with the middle shaft portion; a pinion adapted foraxial and rotary movement on the shaft, said pinion having a portionextending outwardly to form a sleeve and being positioned on the shaftintermediate the threaded sleeve and motor; a drive spring fixed to thethreaded sleeve and adapted for frictional engagement only with thepinion sleeve; and resilientmeans tending to urge the pinion to theouter limit of its axial movement on the shaft.

3. A drive mechanism for engines including a motor shaft having'athreaded portion; a pinion mounted on the shaft for both axial androtary movement; a sleeve element integral with the pinion; a sleevescrew threaded to the shaft and loosely connected to the sleeve element;and a coiled drive spring having one end fixed to thethreadedsleeve andthe other end positioned about the sleeve element and normally freethereof; said pinion upon rotation of the shaft being adapted to bemoved axially into engagement with a member to be started, and saidspring being adapted to frictionally grip the sleeve element to form adrive connection between the shaft and pinion.

4:. In a drive mechanism, in combination with an engine member, a motorshaft having a threaded portion, an inner sleeve loosely mounted on theshaft and having a pinion integral therewith; a second outer sleeve onthe shaft having internal threads cut therein adapted to mesh with thethreaded portion of the motor shaft; means for loosely connecting saidsleeves; a coil spring secured about said sleeves having one end fixedto the outer end of the outer sleeve and the other end having africtional connection to the pinion, said spring being adapted to gripthe inner sleeve when the pinion is moved into mesh with the enginemember.

5. In a drive mechanism for engines the a loose connection becombinationof an engine member, a motor shaft havin a threaded portion; a sleevescrew threaded to said shaft; a coil spring fixed at one end to thethreaded sleevea pinion on the shaft between the threaded sleeve andmotor, said pinion having an outer sleeve portion integral therewith andencircled by said spring; said pinion being movable by said threac edsleeve into mesh with the engine member when the shaft is rotated andmovable by said spring when in complete mesh with said engine member.

6. In a starter mechanism for engines the combination of an enginemember; a motor shaft; a pinion on said shaft axially movable intoengagement with the engine memher when the shaft is rotated, and freelymovable rotatively on the shaft; a sleeve on the shaft having operativeconnection with the shaft and pinion; and means secured to the sleeveeffective to grip the pinion when the shaft is rotated in a direction tomove the pinion into engagement with the engine member.

7. In a starter mechanism for engines, the combination of an enginemember; a motor shaft; an outer sleeve mounted on the shaft for limitedrotary and axial movement; a spring tending to hold said sleeve at theouter limit of its movement in an axial direction; an inner sleevemounted on the shaft, said inner sleeve having free rotation and limitedaxial movement relative to the outer sleeve; a pinion fixed to the innerend of the inner sleeve; a spring fixed to the outer sleeve andencircling both sleeves, operable to form a driving connection betweenthe sleeves when the motor shaft by contracting thereupon; said sleeveshaving sections of reduced outer diameter wherein greater energy isabsorbed by spring contraction than in other sleeve sections.

8. In a drive mechanism for engines the combination of a motor shaft; asleeve operably connected therewith; a pinion mounted on the shaft; anda spring connected at one end to the sleeve and having the other endfree and associated with the pinion, said spring being effective toestablish a frictional driving connection with the pinion when thesleeve is moved relative to the pinion.

9. In a starting mechanism for gas engines, the combination of a motorshaft; a sleeve operably connected therewith; a second sleeve on saidmotor shaft having free rotation on the shaft in inoperative positionand limited axial movement; a pinion secured to said second sleeve; anda coil spring mounted beis rotated to start the engine tween the pinionand first named sleeve, said spring tending to maintain the pinion atthe limit of its axial movement farthest removed from the sleeve andform a frictional driving connection therebetween.

10. In a drive mechanism, the combination. of a power shaft; a sleevemounted in screw threaded engagement with said shaft; a pint ion looselymounted on the shaft; and a yielding friction element fixed at one endto the sleeve and loosely engaging at its other end the pinion, saidspring being adapted to positively engage said pinion when power isbeing transmitted from said shaft through the pinion, said pinion beingadapted to be moved into operative engagement with a member to be driventhrough the screwing movement of the sleeve.

11. In a starting mechanism for non-self starting engines, incombination an engine member; a power driven shaft; a sleeve mounted onsaid shaft for limited rotary movement thereof and for rotary movementtherewith; a pinion freely mounted on said shaft and associated withsaid sleeve; a spring secured to said sleeve and interposed between saidsleeve and pinion for establishing a frictional driving connection ofsaid pinion with said sleeve when said pinion is in engagement with theengine member; and means for automatically disengaging said pinion fromsaid engine member when said pinion is accelerated with respect to saidpower driven shaft.

In testimony whereof, I afiiX my signature.

CARL P. BROCKW'AY.

